reference letters

I'm teaching right now but I don't plan to be there next year. I like my boss but it's just not the school for me. It's a small private school. I'm teaching 3 grades and they really don't pay enough. I'm pretty sure they know I'm looking elsewhere for next year. When would be a good time to ask for a reference letter? I've already started my job search.

Busy people sometimes take a little bit of time to get the letter done.

I would ask now. I wasn't sure if I was staying or not with the job I'm in now (I stayed), but at the time, I asked my boss and told her that I had to start looking now for a summer position since I needed the income. Other people ask and say that it's to update their portfolio, even if they are tenured! You also want to get a letter from any colleague you work well with, and even some parents if this is feasible...you don't want to start the rumor mill going!